**Question **: The probability that a random chosen three-digit number has exactly 3 factors is

(A) 2/225

(B) 7/900

(C) 1/800

(D) none of these

**Answer **: option (B)

**Solution **:

A number has exactly 3 factors if the number is squares of a prime number. Squares of 11, 13, 17,

19, 23, 39, 31 are 3-digit numbers. Hence, the required probability is 7/900